Culture

Easily grown in average, slightly acidic, dry to medium moisture, well-drained soil in full sun to part shade. Best in full sun in the northern part or its growing range, but appreciates some afternoon shade in the St. Louis area. Tolerates a wide range of soil conditions. Prune as needed immediately after bloom and no later than mid-August. Plants may be cut close to the ground in winter to rejuvenate. Plants often struggle in the hot and humid summer climates of the deep South in USDA Zones 8-9.

Noteworthy Characteristics

Physocarpus opulifolius, commonly called ninebark, is an upright, spreading, somewhat coarse, deciduous, Missouri-native shrub which is closely related to genus Spiraea. In Missouri, it typically occurs along streams, rocky banks, gravel bars and in moist thickets, especially in counties south of the Missouri River (Steyermark). Grows 5-9’ tall (less frequently to 10’). Noted for its exfoliating bark (on mature branches) which peels in strips to reveal several layers of reddish to light brown inner bark (hence the common name of ninebark). Bark provides winter interest, but is usually hidden by the foliage during the growing season. Features small pink or white, five-petaled flowers appearing in dense, flat, rounded, 1-2” diameter, spirea-like clusters (corymbs) in late spring. Flowers give way to drooping clusters of reddish fruit (inflated seed capsules). Ovate to rounded, usually 3-5 lobed leaves (to 4” long) are dull green in summer changing to an undistinguished yellow in fall.

Genus name comes from the Greek physa meaning a bladder and karpos meaning fruit, referring to the inflated dry fruits of the plant.

Specific epithet refers to the leaves that resemble those of Viburnum opulus.

Common name of ninebark is in reference to its ornamental attractive exfoliating bark.

‘Center Glow’ is a mounded, vase-shaped, ninebark cultivar that typically matures to 6-8’ tall and as wide, and is most noted for its attractive foliage. It is the result of a cross between P. opulifolius ‘Monlo’ DIABLO (seed parent) and P. opulifolius ‘Dart’s Gold’ (pollen parent). Ovate to rounded, usually 3-lobed, maple-like leaves (to 4” long) emerge greenish-gold in spring but age to burgundy, with leaves showing both colors as they mature. Foliage is nicely complemented by small pinkish-white, five-petaled flowers that bloom in dense, flat, rounded, spiraea-like clusters (corymbs) in late spring. Plants in this genus exhibit exfoliating bark on mature branches. The bark peels in strips to reveal several layers of reddish to light brown inner bark, hence the common name. This interesting bark provides winter interest but is usually hidden by the foliage during the growing season. U.S. Plant Patent PP16,894 was issued on July 25, 2006.

Problems

No serious insect or disease problems. Fireblight and leaf spots may occur.

Reportedly has good resistance to powdery mildew.

Garden Uses

Mass in shrub borders. Effective as hedge, screen or for erosion control on banks. Native plant garden. Able to grow in harsh conditions.